Wednesday, October 06, 2010

Charles Babbage and Climate Change

At the risk of turning into James Burke and creating my own version of Connections, it's amusing to know that two of the topics I've blogged about, Charles Babbage and Climate Change, have a strong connection.

One of the key areas of climate change research used to demonstrate the we live in historically overheated times is dendrochronology (looking at tree rings) to determine past climate (called dendroclimatology). This is a large part of the science behind the Hockey Stick and related controversy.

So, who's the father of dendroclimatology? Charles Babbage has a strong claim.

Babbage wrote in 1838:

It is well known that dicotyledonous trees increase in size by the deposition of an additional layer annually between the wood and the bark, and that a transverse section of such trees presents a series of nearly concentric though irregular rings, the number of which indicates the age of the tree. The relative thickness of these rings depends on the more or less flourishing state of the plant during the years in which they were formed.

[...]

These prominent effects are obvious to our senses, but every shower that falls, every change of temperature that occurs, and every wind that blows, leaves on the vegetable world the traces of its passage; slight, indeed, and imperceptible, perhaps, to us, but not the less permanently recorded in the depths of those woody fabrics. All these indications of the growth of the living tree are preserved in the fossil trunk, and with them also frequently the history of its partial decay.

Let us now inquire into the use we may make of these details relative to individual trees, when examining forests submerged by seas, embedded in peat mosses, or transformed, as in some of the older strata, into stone. Let us imagine, that we possessed sections of the trunks of a considerable number of trees, such as those occurring in the bed called the Dirt-bed in the island of Portland. If we were to select a number of trees of about the same size, we should probably find many of them to have been contemporaries. This fact would be rendered probable if we observed, as we doubtless should do, on examining the annual rings, that some of them conspicuous for their size occurred at the same distances of years in several trees. If, for example, we found on several trees a remarkably large annual ring, followed at the distance of seven years by a remarkably thin ring, and this again, after two years, followed by another large ring, w¨ should reasonably infer that seven years after a season highly favourable to the growth of these trees, there had occurred a season peculiarly unfavourable to them; that after two more years anotherveryfavourable season had happened, and that all the trees so observed had existed at the same period of time. The nature of the season, whether hot or cold, wet or dry, might be conjectured with some degree of probability, from the class of tree under consideration.

[...]

The means of identifying the influence of differentt seasons in various: sections of the same individual tree an its branches being thus attained, the conclusions arrived at must be applied to several trees under similar circumstances, and such modifications must be applied to them as the case may require; and before any general conclusions can be reached respecting a tract of country once occupied by a forest, it will be necessary to have a considerable number of sections of trees scattered over various parts of it.

No comments: